1. Field of the Invention
This invention relates to microbicidal compositions for industrial use, and in particular to slime controlling compositions to be used in pulp and paper manufacturing processes and in industrial cooling water systems, in other words, compositions useful as microbicidal compositions to be used in water systems.
2. Description of the Prior Art
The active ingredient of the compositions of the present invention, namely 4,5-dichloro-1,2-dithiol-3-one, is known to have potent bactericidal and fungicidal activities (Japanese Patent Publication No. 14294/1977). Since this compound is hardly soluble in water, however, compositions in which said compound is made soluble in water are required in order that the compound may be utilized as slime controlling agent in paper manufacturing processes and in industrial cooling water systems. Consequently some compositions have been proposed which employ as surfactant a specific quaternary ammonium salt or a specific pyridinium salt (Japanese Patent Application Laid-Open No. 82723/1976). However, the compositions shown therein by way of examples contain said surfactant in an amount 2.5-5 times as much as that of the active ingredient and that in a water-containing solvent.
There are also known aqueous or nonaqueous compositions wherein a specific quaternary ammonium salt is added in an amount approximately equal to that of a certain active ingredient (methylenebisthiocyanate) which is effective as slime controlling agent useful also in paper manufacturing processes, in expectation of bactericidal activity of said ammonium salt itself (cf. Japanese Patent Publication No. 10927/1975 and No. 21319/1970); and aqueous or nonaqueous compositions including slimicidal ones, wherein nonionic surfactants are added in amounts almost equal to or smaller than those of active ingredients (cf. Japanese Patent Publications Nos. 23897/1973, 23902/1973, 38848/1973 and 21319/1970).
Whereas, as mentioned above, slime controlling compositions for use in paper manufacturing processes should desirably be water-soluble, the active ingredient may be water-insoluble but then the active ingredient is required to be capable of being well dispersed in the form of minute particles. It is of course required that the slime controlling composition should not be corrosive against the machinery, not adversely affect paper in respect of properties thereof, such as sizing degree, brightness, strength, color, etc., and not do any such harm to papermaking as decrease in freeness or in yield. what is more important is that the composition, when used at a necessary concentration, should not cause any foaming. The compositions for use in cooling water systems, too, are naturally required not to cause bubble formation and to have minimal adverse effect on the machinery.